The present invention generally relates to a data communication restriction method, data communication restriction system and mobile terminal.
Recently, the access to the Internet from mobile terminals such as mobile phones is drastically increasing. In order to reduce charges to users for data packet communication, a flat rate service was introduced, in which communication charges are kept constant irrespective of communication quantity. However, users utilizing this service tend to excessively consume a lot of data communication resource, which is a problem.
The flat rate service contracts between users and providers allows the providers to limit or restrict data communication of excessively using flat rate users in order to prevent them from exclusively using of data communication resource. On the other hand, providers are obliged to guarantee communication quality to usage based rate users. Therefore, it is needed to introduce communication restriction systems for guaranteeing communication quality to usage based rate users even at the sacrifice of flat rate users' communication.
This communication restriction should be placed on data communication only but not on voice communication. Accordingly, communication restricted users can utilize voice communication as usual.
FIG. 1 is a conception view for illustrating conventional communication restriction system. In normal operation, a mobile terminal 101 gets access to an external network like the Internet, via an exchange 102 and a relay base station 103. When the relay base station 103 detected excessive accesses from the mobile terminal 101, the relay base station 103 does not relay further access request from the mobile terminal 101 via the exchange 102 to the relay base station 103 any longer.
Many kinds of communication restriction methods for dealing with communication congestion are known. One of them is disclosed in Japanese Patent Laid-open No. 2001-78260. In the communication restriction system disclosed in this document, a base station always monitors communication congestion condition in its radio area, and calculates a congestion level and notifies mobile terminals of the congestion level information. The mobile terminals control their access requests in accordance with the informed congestion level information.
In the communication restriction system shown in FIG. 1, it is possible to prevent from exclusively using communication resource after the relay base station 103. However, since all access requests (re-try requests due to access restriction) repeatedly generated by the mobile terminal 1 pass through the exchange 102, the load of the exchange 102 cannot be reduced.
On the other hand, in the communication restriction system disclosed in Japanese Patent Laid-open No. 2001-78260, communication restriction is placed on many users in accordance with congestion condition in their radio area. It is impossible to restrict only excessively using users among flat rate users. Further, this communication restriction is not only applied to data packet communication but also applied to all communications.